The increased potential for the use of solar energy as a renewable source of energy is well known. The present device provides a low cost alternative to record the amount of sunlight received throughout the day to ascertain the availability of solar power savings in a given location.
It is an object of the device to measure and record the sun's radiance over a long period of time, preferably a year, with reasonable accuracy at a low unit cost. It uses two sensors to measure the sun's radiance; a photodetector and a monocrystalline solar cell. The unit temperature is also measured and saved, as a solar cell's efficiency changes with temperature. The photodetector, solar cell and temperature are periodically measured and saved along with the date and time into a flash RAM storage component.
The photodetector output provides a representation of the amount of sunlight the unit is receiving, but has a smaller collection area than the solar cell. The photodetector output is measured and saved and its secondary function is to indicate a minimum sunlight level with minimal power overhead. To preserve power, measurements are only taken while the sunlight is above the minimum output. The unit's solar cell provides a near identical representation of the solar panels that will ultimately be used by the customer, and can power the device's main circuitry, including the microcontroller.
It is an additional object of the invention to use a USB interface for transferring data to and from the unit to the user PC. The collected sun radiance data and other run-time data is retrieved from the unit. Control parameters, such as the location's date and time, are updated in the device through the USB interface.
It is another object of the invention to provide a variety of mounting means to secure to target locations. Means to secure to angled roofs, curved roofing tiles and flat roofs and windows are provided.